Heretofore, for example, as gas insulated switchgears for use in electric power transmission/distribution and reception facilities, there has been known one which is disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 2007-306701).
In order to reduce differential pressure of a bellows portion of a vacuum interrupter, apart of a vacuum interrupter movable portion (an insulating rod is in high pressure) and the inside of a cylindrical conductor connected to the movable portion are made to communicate with the ambient atmosphere.
That is, a portion which communicates with the inner circumferential side of a bellows 25 and in which a high electric field is not applied is set to atmospheric pressure in order to set the inner circumferential side of the bellows 25 of a vacuum interrupter 10 serving as the vacuum interrupter to the atmospheric pressure. More specifically, the inside of a movable side conductor 35, the inside of a support 7, and the inside of a movable side contact case 8 are set to the atmospheric pressure.
Therefore, a high temperature sealing portion (portion sealed at a high temperature) 37 serving as an airtight sealing portion is provided between the outer circumference of the movable side conductor 35 and a tubular portion 8a of the movable side contact case 8; a high temperature sealing portion 38 serving as an airtight sealing portion is provided between the support 7 and the movable side contact case 8; and a high temperature sealing portion 39 serving as an airtight sealing portion is provided between a movable side end plate 24 of the vacuum interrupter 10 and the movable side contact case 8. Furthermore, in order to set the inside of an insulation support tube 5 to high pressure dry air, a linear sealing portion 40 serving as an airtight sealing portion is provided between an insulation operating rod 12 and the support 7.
Patent Document 1: Japanese Unexamined Patent Publication No. 2007-306701